Conventional wireless access systems provide mechanisms for identification as well as ranging. The identification and ranging mechanisms provide information used to determine whether to allow access to secured areas such as in buildings, secured outdoor areas, and/or vehicles. For example, many automobiles are sold having key fobs that are electronically matched with a particular vehicle and allow a holder of the key fob to gain access to and operate the particular vehicle. The functionality of the key fobs and associated control systems is being increased to response to ever-increasing demands for increased security by individual users and automobile insurance companies, among others.
The key fob is arranged to wirelessly communicate with a base-station control module that is powered by a battery (which often stores upwards of 100 amp-hours) of the particular vehicle. In contrast, the key fob is portable and designed to be light weight and to easily fit in the palm of a hand, pocket, or a purse, for example. As the functionality of the key fob-actuated systems increase, the demand for power by the electronic circuit designs and applications that provide the functionality increase. The increase in power usage can, for example, which can shorten the operating time before having to recharge or replace batteries in the vehicle and/or key fob.